Respuesta :

Answer:

87

Step-by-step explanation:

difference = 7

A1 = 3

so let's imagine this arithmetic sequence as

3, 10, 17, 24 etc....

mathematically the sequence can be described as

An = a1 + (n - 1) d

A13 = 3 + (13 - 1) 7 = 3 + 12*7 = 87